Key Board Problem - Sam4s NR-500 Series Service Manual

8-5 Key Board Problem

Key Board Problem
Key Input
Failure ?
N
Specific Key
Failure?
N
End
SAM4S NR-500 SERIES
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1. Check & Change Key Board Assy
2. Check the KBD Connector on PBA
3. Check the Key Scan Part 74LVC138(U26,U27)
Y
4. Check the Key Return part 74LVC541(U28)
5. Check the related Circuit and Pattern
1. Check the affected Key
Y
2. Check the Matrix Bus & Data Bus
3. Check the Diodes(BAT43WS)
4. Check the Key Board Assy
8 Troubleshooting
8-5